Pubblicazioni

Monitoring storage shelf life of tomato using electronic nose technique

Electronic nose technology offers non-destructive alternative to sense aroma, can be used to assess fruit ripening stage during shelf life. The objective of this study was to monitor tomato storage shelf life during two storage treatments using PEN 2 electronic nose (E-nose). Principal component analysis (PCA) and linear discriminant analysis (LDA) were used to distinguish the different tomato storage time. The obtained results proved that tomato with different storage time can be monitored by the E-nose, but very clear separation among all groups of different storage time was not achieved. By PCA and LDA, E-nose could more clearly discrimination storage time of tomato in carton box than one in folded bag. The correlations between the measured and predicted values of fruit quality attribute (soluble solids content, pH, and puncture force) showed poor prediction performance on the base of signals of E-nose sensors.

05.012015

Evaluation of a portable MOS electronic nose to detect root rots in shade tree species

ABSTRACT The early detection of wood decays in high-value standing trees is very important in urban areas because mitigating control measures must be implemented long before tree failures result in property damage or injuries to citizens. Adverse urban environments increase physiological stresses in trees, causing greater susceptibility to attacks by pathogenic decay fungi. The detection of fungal root rots in urban trees is particularly difficult because conventional detection tools, currently used for diagnosis of wood decays, are not feasible below ground level. Portable electronic olfactory systems or electronic noses (e-noses), currently used in many different scientific fields and industries, previously have been tested for the early diagnosis of wood decay fungi and wood rots. We evaluated the accuracy and effectiveness of the portable PEN3 electronic nose to discriminate between healthy and decayed root segments of five shade trees species, artificially inoculated separately with three species of root-rot fungi and incubated in different soil types under laboratory conditions. The PEN3 e-nose discriminated between healthy and inoculated root fragments and between different decay fungi in different soil types for most host-fungus combinations, but the discrimination power of this e-nose varied depending on tree species and strain of root-rot fungus analyzed. We provide explanations for the ineffectiveness of the e-nose to detect low levels of decay for certain host-fungus combinations. The advantages of e-nose detection over conventional wood decay detection tools also are discussed.

Antibiotics are routinely added to milk products and pose potential harm to public health. The objective of this study was to use an innovative and nondestructive application of an electronic nose instrument for rapid detection of penicillin G in goat milk. The PEN3 electronic nose system was utilized to detect volatile substances in goat milk after the addition of penicillin G sodium salt at concentrations of 0, 50, 100 and 200 μg/L. The data were extracted at 60 s to carry out a linear discriminant analysis. Additional statistical analysis was conducted using neural networks to predict the penicillin G concentration in goat milk samples. Accuracy rates for the two methods were 98.0 and 96.7% for training samples, and 97.0 and 94.9% for testing samples, respectively. The results from this study show that the electronic nose system can be utilized to predict the penicillin G concentrations in goat milk samples.Practical ApplicationsAntibiotics are routinely added to animal-derived food products and have been reported to cause potential harm to human health. However, traditional analytical chemical methods (i.e., gas, liquid and high-performance liquid chromatography) can detect trace amounts of additives and have some drawbacks, such as complicated operation, high costs of implementation and lengthy analysis time. This research has examined the feasibility, accuracy and effectiveness of a metal oxide semiconductor gas sensor type electronic nose device (the PEN3 e-nose) to detect and discriminate among different concentrations of penicillin G in goat milk. Data from this study show that the electronic nose system can be used to predict the penicillin G concentration in goat milk samples.

24.082014

Noses for Surveillance of Wastewater from Secondary Treatment Plants in Alexandria, Egypt

Intermittent discharges of industrial chemical pollutants into sewers can have a damaging effect on the processes involved in treating wastewater. They are sometimes able to pass through treatment plants and enter into the receiving water, to exert a harmful effect on the environment and possibly pass down a river to the intakes forwater supplies. We evaluated the use of an electronic nose (E-Nose) consisting of ten non-specific metal oxide sensors for monitoring odors of wastewater from influent and effluent samples at three different wastewater secondary treatment plants in Alexandria, Egypt, over a 7-month period in association with causes of odor by standard laboratories of chemical analysis. We analyzed E-Nose sensor responses of all plants using the principal component analysis (PCA), which allowed interpretation and differentiation of samples in terms of origin and quality along the study period. E-Nose sensor responses for influent and final effluent samples from the three secondary treatment plants were significantly associated with Hydrogen Sulphide, Ammonia and Nitrate. Thus, the E-Nose can be used as a rapid alarm generator towards volatile compounds, e.g. in specific advanced treatment processes to produce claimed water from effluent of the domestic wastewater treatment plant under scrutiny... Wastewater arriving at sewage treatment plants is highly variable in nature, due to the diurnal nature of human activity and the environmental factors such as rainfall, in addition to shorter term variability effects due to intermittent or accidental discharges of chemical pollutants into sewers (Baawain 2013, Leusch 2013). These latter discharges, usually of industrial origin, can have a damaging effect on the processes involved in treating wastewater and are sometimes able to pass through treatment plants and ...

As an exotic highly perishable tropical fruit commercially grown in Colombia, soursop (Annona muricata L.) is currently in need of postharvest handling studies. Thus, the present research was conducted to characterize the volatile compounds of soursop cv. Elita during postharvest. For this purpose, fruit ripeness was evaluated, for one thing, by a volatile compound measuring system known as electronic nose (EN), and for another thing, by headspace solid phase microextraction and gas chromatography mass spectrometry (HS-SPME/GC-MS). The profile of volatile substances in fruits is one of the main indicators of the sensory attributes that typify the organoleptic quality of these products. The EN constitutes an economical, relatively simple, fast and innovative alternative to determine groups of volatile compounds in whole or fractionated samples from fruits of commercial interest. In contrast, and despite its being a highly selective technique, the use of SPME/CG-MS might be limited by its elevated cost. Based on EN assessment, fruit ripening stages were classified as unripe, half ripe, ripe and overripe. The most active EN sensors were numbers 2 sensitive to nitrogen oxides), 6 (sensitive to methane) and 8 (sensitive to alcohols and partially aromatic compounds). HS-SPME/GC-MS analysis allowed establishing that during postharvest, the major proportion of volatile compounds corresponded to esters, predominantly Methyl hexanoate. Particularly in overripe fruits, the presence of alcoholic compounds coincides with the EN assessment, which, for its part, detected mainly alcohols and a wide range of aromatic substances. The study contributes to the characterization of postharvest volatiles, which are one of the major sensory attributes of tropical fruits.

20.022013

Electronic nose evaluation of volatile emission of Chinese teas: from leaves to infusions

An electronic nose can be used to discriminate tealeaf quality, but to the best of the author's knowledge, studies that address the changes in electronic sensor signals between tea leaves and infusions are not available. In this framework, this preliminary work compared the volatile emissions of leaf samples belonging to the basic Chinese teas (white, yellow, green, oolong, black and pu erh) with those of their respective infusions using an electronic nose. Different signal responses were qualitatively and quantitatively obtained from the sensors both for the tea leaves and their respective infusions, showing that the leaf aroma is not transferred as it is into the beverage. The teas were grouped according to the different fermentation techniques based on the percentage variations in the sensor contributions to the complete description of the volatile profiles. The results indicated that the electronic nose is a suitable tool to monitor the volatile emission differences that occur between leaves and infusions in different tea types